Swift-根据坐标和时间改变星图 View

Question

我正在尝试找出根据用户的时间和坐标来校正我的星图 View 的方法，但它不是很准确，所以我想知道哪一部分是错误的。

我有两个节点，星图节点和相机节点，相机节点位于星图节点内部，使其看起来像 360 度 View 。这是我的方法:

1.获取加速度数据

motionManager.startAccelerometerUpdatesToQueue(NSOperationQueue.currentQueue()!, withHandler: {(accelerometerData, error) -> Void in

    self.outputAccelerationData(accelerometerData!.acceleration)

    if(error != nil) {
        print("\(error)")
    }
})

func outputAccelerationData(acceleration: CMAcceleration) {

    let accZ: Double = fabs(acceleration.z)
    rotateDegreeCameraX = acos(accZ) * 180 / M_PI

}

1. 将相机节点更正到它正在看的地方

//让相机节点从看春分开始//

  private func orientationFromCMQuaternion(attitudeQuaternion: CMQuaternion, trueHeading: Float) -> SCNVector4 { 
    let gq1 = GLKQuaternionMakeWithAngleAndAxis(GLKMathDegreesToRadians(Float(rotateDegreeCameraX) - 90), 1, 0, 0)
    let gq2 = GLKQuaternionMakeWithAngleAndAxis(GLKMathDegreesToRadians(180), 0, 0, 1)
    let gq3 = GLKQuaternionMakeWithAngleAndAxis(GLKMathDegreesToRadians(trueHeading), 0, 0, 1)       
    let gq4 = GLKQuaternionMake(Float(attitudeQuaternion.x), Float(attitudeQuaternion.y), Float(attitudeQuaternion.z), Float(attitudeQuaternion.w))

    let qp = GLKQuaternionMultiply(gq1, gq2)
    let qp2 = GLKQuaternionMultiply(qp, gq3)
    let qp3 = GLKQuaternionMultiply(qp2, gq4)
    let rq = CMQuaternion(x: Double(qp3.x), y: Double(qp3.y), z: Double(qp3.z), w: Double(qp3.w))
    return SCNVector4Make(Float(rq.x), Float(rq.y), Float(rq.z), Float(rq.w))
}

1. 根据用户的时间坐标校正星图(SCNshpere)

   func correctOfSkyMap(revolution: Float, rotation: Float, latitude: Float) -> SCNVector4 {

    // rotate the sphere, making Equatorial plane is now same position with Ecliptic plane. (degrees: 23.4397) //
    let gq = GLKQuaternionMakeWithAngleAndAxis(GLKMathDegreesToRadians(-23.4397), 0, 0, 1)
   
    // rotate the sphere according to the gap between current date and the date vernal equinox pass 0 longitude //
    let gq2 = GLKQuaternionMakeWithAngleAndAxis(GLKMathDegreesToRadians(-revolution), 0, 1, 0)
    let qp = GLKQuaternionMultiply(gq, gq2)
   
    // rotate sphere back to where Equatorial plane is //
    let gq3 = GLKQuaternionMakeWithAngleAndAxis(GLKMathDegreesToRadians(-23.4397), 0, 0, 1)
    let qp2 = GLKQuaternionMultiply(qp, gq3)
   
    // rotate the sphere according to current time //
    let gq4 = GLKQuaternionMakeWithAngleAndAxis(GLKMathDegreesToRadians(-rotation), 0, 1, 0)
    let qp3 = GLKQuaternionMultiply(qp2, gq4)
   
    // rotate sphere according to user's latitude (adjust the degree of polaris) //
    let gq5 = GLKQuaternionMakeWithAngleAndAxis(GLKMathDegreesToRadians(latitude - 90), 1, 0, 0)
    let qp4 = GLKQuaternionMultiply(qp3, gq5)
   
    // after comparing with other star gazing app, finding the map needs to rotate 90 degrees to make it more accurate. //
    let gq6 = GLKQuaternionMakeWithAngleAndAxis(GLKMathDegreesToRadians(90), 0, 0, 1)
    let qp5 = GLKQuaternionMultiply(qp4, gq6)
   
    return SCNVector4Make(qp5.x, qp5.y, qp5.z, qp5.w)   }
   

2. 下面是计算公转和自转的方法:

   func calculateRevolution() -> float {

   let degreePerDay: Double = 0.9656112744
   let originalDate = NSDate()
   let dateFormatter = NSDateFormatter()
   dateFormatter.dateFormat = "yyyy-MM-dd HH:mm"
   dateFormatter.timeZone = NSTimeZone(abbreviation: "UTC")
   let currentDateStr = dateFormatter.stringFromDate(originalDate)
   if let currentDate = dateFormatter.dateFromString(currentDateStr),
       let vernalEquinox = dateFormatter.dateFromString("2016-03-20 04:30") {
   
       let currentDateInSecs = currentDate.timeIntervalSinceDate(vernalEquinox)
       let currentDateInDays = currentDateInSecs / (60 * 60 * 24)
       let rotateDegreesDouble = currentDateInDays * degreePerDay
       let rotateDegrees = Float(rotateDegreesDouble)
   
       return rotateDegrees
   
   } else { return 0.0 }}
   

   func calculateEarthRotation() -> Float {

   let degreePerMinute: Double = 0.25
   let originalDate = NSDate()
   let dateFormatter = NSDateFormatter()
   dateFormatter.timeZone = NSTimeZone(abbreviation: "UTC")
   dateFormatter.dateFormat = "yyyy-MM-dd HH:mm"
   let originalDateStr = dateFormatter.stringFromDate(originalDate)
   if let currentDate = dateFormatter.dateFromString(originalDateStr) {
       let calendar = NSCalendar.currentCalendar()
       let hours = Double(calendar.component(.Hour, fromDate: currentDate))
       let minutes = Double(calendar.component(.Minute, fromDate: currentDate))
   
       print("pass time: \(hours * 60 + minutes)")
       print("Local date: \(originalDate)")
       print("Date in UTC: \(currentDate)")
   
       return Float((hours * 60 + minutes) * degreePerMinute)
   
   } else {return 0.0}}
   

任何人都可以给我一些建议以使其准确吗？提前致谢。

Answer 1

缩小错误范围。有太多的事情可能是错误的，任何人都无法检查。

赤经/偏角是否正确？你怎么知道？

对于给定的 RA/decl，您的恒星是否出现在外球体的正确位置？你怎么知道？

看看https://stackoverflow.com/help/mcve并发布我们可以运行并重现您的错误的 Playground 兼容代码片段。

带评论的屏幕截图也会有所帮助。